Studies on the Population Dynamics of Trichoderma Spp. In Soil and Its Antagonistic Activity Against Fusarium Oxysporum F. Sp. Lentis

Abstract

Lentil is an important pulse crop cultivated all across the globe. It is a major pulse crop in terms of its nutrient composition and is consumed by a large population all around the world. Fusarium oxysporum f. sp. lentis is a major pathogen of lentil causing wilt disease in the crop. The yield losses caused due to the disease may even reach upto 100 percent depending on the severity of infection. Trichoderma spp. are an effective biocontrol agent for the management of pathogens affecting various crops. The present study was conducted to understand the population dynamics of the bioagent in soil and to study the antagonistic activity of the bioagent against fusarium wilt of lentil under pot conditions. For the purpose SV3 strain of T. harzianum was used. The strain was multiplied on five different substrates viz. bajra grains, wheat grains, wheat straw, cotton cake and neem cake + cow dung (1:9) mixture, before applying to the soil. The neem cake + cow dung mixture proved to be the best in supporting the growth and the viability of the bioagent in soil for a longer time. The wheat grains were found to be the next best substrate for maintaining a good population dynamics of the bioagent followed by that of bajra grains. The bajra grains and the wheat grains as substrate for SV3 reduced the wilt disease incidence of lentil significantly. Neem cake + cow dung was found to be the next best substrate in terms of reducing the disease incidence in the crop. In addition to maintaining a good population count, soil application of SV3 mass multiplied on neem cake + cow dung (1:9) mixture also significantly increased the yield, shoot length, root length, plant height and fresh weight of lentil as well. This was followed by soil application of SV3 mass multiplied on bajra grains and wheat grains. The cotton cake and wheat straw exhibited a poor performance as substrates for SV3 strain of T. harzianum in terms of maintaining population levels of the bioagent in soil and reducing the wilt incidence. The biometric parameters of lentil plants also didn’t show much improvement in soil applied with SV3 mass multiplied on cotton cake and wheat straw. Overall, it was seen that the substrates on which the bioagent was multiplied had a significant effect over the population dynamics of the bioagent in soil, wilt incidence and the biometric parameters of the crop. Thus, the performance of the bioagent could be improved with the use of substrates suitable for its growth and multiplication.